硫离子掺杂促进WO_(3)纳米线高效光催化降解甲苯  

SULFIDE ION DOPING PROMOTES EFFICIENT PHOTOCATALYTIC DEGRADATION OF TOLUENE BY WO_(3) NANOWIRES

作　　者：李海诚 程铖 陈政霖 杨丽霞[1] 罗胜联[1] LI Haicheng;CHENG Cheng;CHEN Zhenglin;YANG Lixia;LUO Shenglian(Key Laboratory of Jiangxi Province for Persistent Pollutants Prevention Control and Resource Reuse,School of Environmental and Chemical Engineering,Nanchang Hangkong University,Nanchang 330063,China)

机构地区：[1]南昌航空大学环境与化学工程学院持久性污染物防治与资源化江西省重点实验室,南昌330063

出　　处：《环境工程》2024年第9期201-210,共10页Environmental Engineering

摘　　要：通过外加H_(2)O_(2)溶解固态钨网上表层钨单质并产生过氧钨酸,同时在前驱体溶液中加入硫代乙酰胺,结合水热合成法与煅烧法制备得到S^(2-)掺杂的WO_(3)光催化纳米线(标记为S-WO_(3)),构建了氧空位介导的高活性亲水/亲氧光催化反应系统,深入探讨了S掺杂及氧空位对促进原始WO_(3)光催化性能及自由基生产能力的内在机制,并通过一系列甲苯的光催化降解实验验证了其污染治理能效。结果表明:S-WO_(3)在90 min内对甲苯的去除率为91.7%,是原始WO_(3)的3.3倍;其对应的CO_(2)转化率为90.1%,是原始WO_(3)的15.8倍。X射线衍射(XRD,X-ray diffraction)和电子扫描电镜(SEM,scanning electron microscope)结果显示,S^(2-)掺杂会引起WO_(3)晶格畸变和应力场导致晶体重新定向生长,使WO_(3)从纳米块状结构转变成纳米线状结构,因此S-WO_(3)纳米线具有比原始WO_(3)更大的比表面积,光吸收能力增强。此外,电子顺磁共振(EPR,electron paramagnetic resonance)结果表明:S^(2-)掺杂也会引起WO_(3)晶格中氧空位产生,并作为电子陷阱捕获光生电子,促进载流子分离,提高光电转换效率。同时,与原始WO_(3)相比,S-WO_(3)亲水性变大,能更加有效地吸附水分子和氧分子,增大被空穴氧化和光电子还原概率,生成强氧化性羟基自由基(·OH)和超氧自由基(·O_(2)^(-))。综上,S^(2-)掺杂显著增强了WO_(3)降解矿化甲苯能力。且由于S-WO_(3)直接生长在钨网上,这种自支撑特性使其物化性能稳定,连续5次循环实验,其甲苯降解效率未见衰减,且反应过程中不产生苯等有毒中间体。相关研究结果展示了S-WO_(3)催化剂作为高效持久降解VOCs的催化能力和实际应用前景。Sulfide-doped WO_(3) catalyst(S-WO_(3))was prepared through hydrothermal synthesis and calcination methods with thioacetamide and peroxytungstic acid as precursors.The peroxytungstic acid was produced by dissolving tungsten in H_(2)O_(2) aqueous solution.This study established an oxygen vacancy-mediated,highly active hydrophilic/oxygenophilic photocatalytic reaction system.It also delved into the intrinsic mechanisms by which sulfur doping and oxygen vacancies enhance the photocatalytic performance and reactive oxygen species generation capabilities of pristine WO_(3).The efficacy of this system for environmental remediation was substantiated through a series of photocatalytic degradation experiments involving toluene.Notably,S-WO_(3) achieved a toluene removal rate of 91.7%within 90 minutes,3.3 times that of the original WO_(3);the CO_(2) conversion rate reached 90.1%,15.8 times that of the original WO_(3).The XRD and SEM results show that S^(2-)doping causes lattice distortion and stress fields in WO_(3),leading to the redirection of crystal growth and transforming the structure from nano-blocks to nano-wires.The S-WO_(3) nanowires exhibit a larger specific surface area and a higher density of active sites than WO_(3),facilitating the deep degradation of toluene.Furthermore,EPR results suggested that S^(2-)doping induces oxygen vacancies in WO_(3),which act as electron traps to capture photogenerated electrons and facilitate charge carrier separation,thereby enhancing photocatalytic performance.Contact angle experiments indicated that S-WO_(3) exhibited stronger hydrophilicity compared to pristine WO_(3),effectively adsorbing water molecules and oxygen molecule,and facilitating their oxidation into the highly oxidative·OH radical and·O_(2)^(-) radical.In a word,S^(2-)doping enables WO_(3) superior degradative and mineralization capabilities for toluene.Moreover,for the self-supporting properties,the S-WO_(3) nanowires consistently maintain high photocatalytic activity for toluene degradation even after five s

关 键 词：光催化 甲苯 S-WO_(3) 氧空位 载流子 掺杂 

分 类 号：X701[环境科学与工程—环境工程]